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CastCheck methodology v0.2 · data through 2026-08-30

San Diego Lindbergh · NCEP GFS · lead day 1

KSAN · gfs · lead 1

Target day = initialization date + 1 day. This page is a permanent link: the numbers change as history accumulates, the address and the methodology version do not.

Scores use the latest model version segment, gfs-0p25, starting 2026-08-01 — days before that ran a different version of the model and are excluded rather than silently pooled. Of the scored days, 1 carry a QC flag on the observation.

JSON for this page CSV of the daily errors Cite this page

Every number for this combination

All four windows × both initializations × both interpolations × both variables. Errors are computed in °C and shown in °F; CI is a 95 % moving-block bootstrap interval. MAE debiased and skill, debiased remove the constant offset of the window first, so a station that the model always reads a degree too warm is not scored as if it had no skill — compare the two skill columns to see how much of the error is a fixed offset. n QC next to n counts days whose observation carries a QC flag.

VariableInitMethod Windown MAE °F MAE debiased Bias °F RMSE °F ±1 °F±2 °F±3 °F Skill Skill, debiased Period
tmax00Zbilinear30d29 1 QC2.68 [2.02, 3.34]1.46-2.65 [-3.32, -1.93]3.27 [2.43, 4.06]17% [7%, 32%]45%59%-0.47+0.202026-08-02 → 2026-08-30
tmax00Zbilinear90d29 1 QC2.68 [1.88, 3.30]1.46-2.65 [-3.30, -1.77]3.27 [2.32, 4.04]17% [7%, 33%]45%59%-0.47+0.202026-08-02 → 2026-08-30
tmax00Zbilinear365d29 1 QC2.68 [1.82, 3.39]1.46-2.65 [-3.39, -1.72]3.27 [2.27, 4.20]17% [5%, 35%]45%59%-0.47+0.202026-08-02 → 2026-08-30
tmax00Zbilinearall29 1 QC2.68 [1.78, 3.43]1.46-2.65 [-3.43, -1.67]3.27 [2.27, 4.15]17% [5%, 37%]45%59%-0.47+0.202026-08-02 → 2026-08-30
tmax00Znearest30d29 1 QC5.05 [4.30, 5.80]1.37-5.05 [-5.80, -4.30]5.42 [4.59, 6.39]0% [0%, 0%]3%10%-1.76+0.252026-08-02 → 2026-08-30
tmax00Znearest90d29 1 QC5.05 [4.17, 5.72]1.37-5.05 [-5.72, -4.17]5.42 [4.40, 6.30]0% [0%, 0%]3%10%-1.76+0.252026-08-02 → 2026-08-30
tmax00Znearest365d29 1 QC5.05 [4.14, 5.89]1.37-5.05 [-5.89, -4.14]5.42 [4.38, 6.46]0% [0%, 0%]3%10%-1.76+0.252026-08-02 → 2026-08-30
tmax00Znearestall29 1 QC5.05 [4.08, 5.93]1.37-5.05 [-5.93, -4.08]5.42 [4.33, 6.44]0% [0%, 0%]3%10%-1.76+0.252026-08-02 → 2026-08-30
tmax12Zbilinear30d29 1 QC2.91 [2.27, 3.49]1.32-2.91 [-3.49, -2.27]3.33 [2.72, 3.87]14% [3%, 29%]34%45%-0.59+0.282026-08-02 → 2026-08-30
tmax12Zbilinear90d29 1 QC2.91 [2.14, 3.45]1.32-2.91 [-3.45, -2.14]3.33 [2.60, 3.84]14% [0%, 31%]34%45%-0.59+0.282026-08-02 → 2026-08-30
tmax12Zbilinear365d29 1 QC2.91 [2.10, 3.53]1.32-2.91 [-3.53, -2.10]3.33 [2.56, 3.94]14% [0%, 31%]34%45%-0.59+0.282026-08-02 → 2026-08-30
tmax12Zbilinearall29 1 QC2.91 [2.00, 3.56]1.32-2.91 [-3.56, -2.00]3.33 [2.50, 3.95]14% [0%, 33%]34%45%-0.59+0.282026-08-02 → 2026-08-30
tmax12Znearest30d29 1 QC5.33 [4.68, 6.00]1.16-5.33 [-6.00, -4.68]5.57 [4.91, 6.32]0% [0%, 0%]0%7%-1.92+0.372026-08-02 → 2026-08-30
tmax12Znearest90d29 1 QC5.33 [4.54, 5.96]1.16-5.33 [-5.96, -4.54]5.57 [4.78, 6.31]0% [0%, 0%]0%7%-1.92+0.372026-08-02 → 2026-08-30
tmax12Znearest365d29 1 QC5.33 [4.54, 6.08]1.16-5.33 [-6.08, -4.54]5.57 [4.75, 6.40]0% [0%, 0%]0%7%-1.92+0.372026-08-02 → 2026-08-30
tmax12Znearestall29 1 QC5.33 [4.46, 6.09]1.16-5.33 [-6.09, -4.46]5.57 [4.69, 6.37]0% [0%, 0%]0%7%-1.92+0.372026-08-02 → 2026-08-30
tmin00Zbilinear30d29 1 QC2.37 [1.65, 3.17]1.26+2.26 [1.39, 3.16]2.79 [1.98, 3.54]14% [3%, 25%]41%72%-2.13-0.532026-08-02 → 2026-08-30
tmin00Zbilinear90d29 1 QC2.37 [1.62, 3.20]1.26+2.26 [1.33, 3.20]2.79 [1.94, 3.54]14% [0%, 27%]41%72%-2.13-0.532026-08-02 → 2026-08-30
tmin00Zbilinear365d29 1 QC2.37 [1.56, 3.27]1.26+2.26 [1.25, 3.26]2.79 [1.88, 3.60]14% [0%, 29%]41%72%-2.13-0.532026-08-02 → 2026-08-30
tmin00Zbilinearall29 1 QC2.37 [1.61, 3.33]1.26+2.26 [1.31, 3.33]2.79 [1.93, 3.62]14% [0%, 28%]41%72%-2.13-0.532026-08-02 → 2026-08-30
tmin00Znearest30d29 1 QC1.74 [1.30, 2.22]1.09+1.53 [0.87, 2.16]2.08 [1.54, 2.60]28% [17%, 38%]69%83%-1.29-0.332026-08-02 → 2026-08-30
tmin00Znearest90d29 1 QC1.74 [1.28, 2.25]1.09+1.53 [0.84, 2.20]2.08 [1.50, 2.60]28% [17%, 38%]69%83%-1.29-0.332026-08-02 → 2026-08-30
tmin00Znearest365d29 1 QC1.74 [1.23, 2.31]1.09+1.53 [0.74, 2.24]2.08 [1.42, 2.64]28% [15%, 39%]69%83%-1.29-0.332026-08-02 → 2026-08-30
tmin00Znearestall29 1 QC1.74 [1.26, 2.33]1.09+1.53 [0.79, 2.29]2.08 [1.47, 2.66]28% [15%, 39%]69%83%-1.29-0.332026-08-02 → 2026-08-30
tmin12Zbilinear30d29 1 QC2.12 [1.36, 2.99]1.18+2.00 [1.10, 2.96]2.50 [1.62, 3.30]17% [3%, 31%]48%76%-1.80-0.442026-08-02 → 2026-08-30
tmin12Zbilinear90d29 1 QC2.12 [1.33, 3.01]1.18+2.00 [1.06, 3.00]2.50 [1.60, 3.33]17% [0%, 33%]48%76%-1.80-0.442026-08-02 → 2026-08-30
tmin12Zbilinear365d29 1 QC2.12 [1.29, 3.08]1.18+2.00 [1.01, 3.07]2.50 [1.54, 3.36]17% [0%, 33%]48%76%-1.80-0.442026-08-02 → 2026-08-30
tmin12Zbilinearall29 1 QC2.12 [1.32, 3.12]1.18+2.00 [1.05, 3.12]2.50 [1.55, 3.37]17% [0%, 33%]48%76%-1.80-0.442026-08-02 → 2026-08-30
tmin12Znearest30d29 1 QC1.52 [1.04, 2.10]0.99+1.33 [0.66, 2.04]1.86 [1.24, 2.42]38% [17%, 57%]76%93%-1.01-0.212026-08-02 → 2026-08-30
tmin12Znearest90d29 1 QC1.52 [1.02, 2.10]0.99+1.33 [0.62, 2.06]1.86 [1.19, 2.42]38% [15%, 59%]76%93%-1.01-0.212026-08-02 → 2026-08-30
tmin12Znearest365d29 1 QC1.52 [0.97, 2.15]0.99+1.33 [0.55, 2.11]1.86 [1.16, 2.45]38% [14%, 61%]76%93%-1.01-0.212026-08-02 → 2026-08-30
tmin12Znearestall29 1 QC1.52 [0.99, 2.17]0.99+1.33 [0.61, 2.15]1.86 [1.15, 2.46]38% [14%, 60%]76%93%-1.01-0.212026-08-02 → 2026-08-30

+ model too warm · − model too cold · bias interval includes zero · ★ lowest MAE · = not distinguishable from the leader · ▼ significantly worse · n < 30 greyed and unranked · CI is a 95 % moving-block bootstrap interval.

Daily error, last 90 days

Daily forecast minus observed error in °F for NCEP GFS at KSAN, lead day 1, 00Z bilinear tmax+10+50-5-102026-08-02: -1.13 °F2026-08-03: -0.33 °F2026-08-04: +0.47 °F2026-08-05: -2.99 °F2026-08-06: -3.82 °F2026-08-07: -1.93 °F2026-08-08: -0.14 °F2026-08-09: -3.04 °F2026-08-10: -3.75 °F2026-08-11: -2.43 °F2026-08-12: -4.68 °F2026-08-13: -4.03 °F2026-08-14: -4.27 °F2026-08-15: -3.41 °F2026-08-16: -1.76 °F2026-08-17: -1.97 °F2026-08-18: -1.33 °F2026-08-19: -0.54 °F2026-08-20: -3.35 °F2026-08-21: -3.42 °F2026-08-22: -1.46 °F2026-08-23: -4.56 °F2026-08-24: -1.85 °F2026-08-25: -2.61 °F2026-08-26: -9.3 °F2026-08-27: -2.17 °F2026-08-28: -0.44 °F2026-08-29: -4.98 °F2026-08-30: -1.53 °F2026-08-022026-08-30°F, forecast − observed
Forecast − observed, °F, 00Z bilinear daily maximum. The dashed line is zero; the thick line is a centred 7-day mean, drawn only where the whole window is present. Gaps are days with no score, never interpolation. Hover a point for its date and value.
The same series as a table (29 days, newest first) · download CSV
Climatological dayError °F
2026-08-30-1.53
2026-08-29-4.98
2026-08-28-0.44
2026-08-27-2.17
2026-08-26-9.30
2026-08-25-2.61
2026-08-24-1.85
2026-08-23-4.56
2026-08-22-1.46
2026-08-21-3.42
2026-08-20-3.35
2026-08-19-0.54
2026-08-18-1.33
2026-08-17-1.97
2026-08-16-1.76
2026-08-15-3.41
2026-08-14-4.27
2026-08-13-4.03
2026-08-12-4.68
2026-08-11-2.43
2026-08-10-3.75
2026-08-09-3.04
2026-08-08-0.14
2026-08-07-1.93
2026-08-06-3.82
2026-08-05-2.99
2026-08-04+0.47
2026-08-03-0.33
2026-08-02-1.13

Error distribution

Distribution of the signed daily error in °F for NCEP GFS at KSAN, lead day 1-10 to -9 °F: 1 day-9 to -8 °F: 0 days-8 to -7 °F: 0 days-7 to -6 °F: 0 days-6 to -5 °F: 0 days-5 to -4 °F: 5 days-4 to -3 °F: 6 days-3 to -2 °F: 4 days-2 to -1 °F: 8 days-1 to 0 °F: 4 days0 to 1 °F: 1 day1 to 2 °F: 0 days2 to 3 °F: 0 days3 to 4 °F: 0 days4 to 5 °F: 0 days5 to 6 °F: 0 days6 to 7 °F: 0 days7 to 8 °F: 0 days8 to 9 °F: 0 days9 to 10 °F: 0 daysdashed: P50 |e| 2.43 · P90 |e| 4.59 °F-100+10 °Fn = 29 days
All scored days for 00Z bilinear daily maximum, 20 equal bins. The dashed marks are the 50th and 90th percentiles of the absolute error, mirrored on both sides. Hover a bar for its bin and count.
Bin counts as a table
From °FTo °FDays
-10.00-9.001
-9.00-8.000
-8.00-7.000
-7.00-6.000
-6.00-5.000
-5.00-4.005
-4.00-3.006
-3.00-2.004
-2.00-1.008
-1.00+0.004
+0.00+1.001
+1.00+2.000
+2.00+3.000
+3.00+4.000
+4.00+5.000
+5.00+6.000
+6.00+7.000
+7.00+8.000
+8.00+9.000
+9.00+10.000

Month by month

00Z bilinear daily maximum, newest first.

Monthn MAE °FBias °F
2026-08292.68 -2.65

Availability

ModelScored period DaysCoverage
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29
NCEP GFS2026-08-02 → 2026-08-30 29

Compared with other models

Paired bootstrap on the days both models cover (90d, 00Z, bilinear, daily maximum). Negative means NCEP GFS has the lower MAE. "Distinguishable" means the 95 % interval excludes zero.

Other modelCommon days MAE difference °FDistinguishable
ECMWF AIFS Single 29 -1.13 [-2.08, -0.19] yes
Aurora (GFS init) 1 -2.54 [-2.54, -2.54] yes
Aurora (IFS init) 2 -1.93 [-2.16, -1.69] yes
FourCastNet v2 (GFS init) 1 +0.98 [0.98, 0.98] yes
FourCastNet v2 (IFS init) 2 +0.70 [0.02, 1.37] yes
GraphCast (GFS init) 1 -1.98 [-1.98, -1.98] yes
GraphCast (IFS init) 27 -3.10 [-3.98, -2.17] yes
ECMWF IFS HRES 22 -2.73 [-3.59, -2.19] yes
Pangu-Weather (GFS init) 1 -3.45 [-3.45, -3.45] yes
Pangu-Weather (IFS init) 2 -3.15 [-3.34, -2.97] yes
Persistence (baseline) 29 +0.85 [-0.45, 1.75] no

Cite this page

ShortCastCheck, KSAN gfs lead 1, methodology v0.2, accessed 2026-08-31, https://castcheck.zifanzhang.com/station/KSAN/model/gfs/lead/1/

LongCastCheck (2026). Station-level verification of raw weather-model 2 m temperature forecasts: KSAN (San Diego Lindbergh), model gfs, lead day 1. Methodology version 0.2, schema version 0.1, data through 2026-08-30. Accessed 2026-08-31. https://castcheck.zifanzhang.com/station/KSAN/model/gfs/lead/1/

Accessed2026-08-31 (data through 2026-08-30; page built 2026-08-31T03:52:06+00:00)

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